Process for floating uranium ores particularly carnotite



UNITED STATES PATENT OFFICE PROCESS FOR FLOATING URANIUM ORES PARTICULARLY CABNOTITE Harry Howard Armstrong and Arthur Burley Men'efee, Los Angelea, Calif.

No Drawing. Application January 30, 1933,

- Serial No. 654,238

17 Claims. (Cl. 209-166)- Up to the present, the flotation of camotite scrapin off, th s sepa atin t fro the zansue has been an operation of extreme difliculty or materials. impossibility. As late as 1930, the U. S. Bureau The froth from the first or rougher cell or unit of Mines in its pamphlet Reports of Investigais usually recleaned y fleeting again in Oth ti N 3057, states on page 4: The usual cells according to ordinary practice. The final 5 methods for concentrating ores, such as flotation ncentrate from a uranium ore like camotite or tabling, have not been successfully applied to rry fr m n to hr p rcen Usos results camotites. in product containing from 8% to 30% U308 by The object of this invention is to provideaproc- W t- With some Ores the addition of some 10 ess whereby camotite and other uranium ores ca p ant uch as Sodium silicate is re- 10 including substantially all of its uranium and qu ed to bring up e co tra to these h h radium values, can be cleanly separated from its contents of uranium. From on h lf p n to siliceous gangue by flotation. Torbernite, autufi P d is the range of d p a p ton of nite and the uraninites are other ores which may t y b d y in e Cleaning 0 fi a b treated by our process. operation or it may be used in all the cell steps. 15

The first step in the process is to grind or crush The amounts the reagents required V y Widely the camotite finely, say to 60 mesh or finer, The according to the uranium and other component crushing may be done wet or dry, parts of the ore, especially the gangue materials The second step is to tr at the cru h d re and in particular calcium materials and finally in which has been made t a t pulp, usually the degree of softness of the water. As an ex- 20 with soft water, then with either a dilute solup 8- typieel camotite ore is One Varying in tion of a sodium or potassium soap or to agitate the U30. content from 1% to 5% and the usual the pulp with a fatty acid, such as lauric, or do range of reagents will be as o ow both. In this step the camotite particles are p from D ten to 10 l p r ncontacted with the soap or fatty acid or both and Fatty id r m l p r t to 6 l per ten. 25 the effect is, that they are conditioned and will The fatty acids which are Solids at o m separate from th gangue under t subsequent peratures, for example stearic, lauric or palmitic, treatment. This process of contacting may be 841! dissolved in Solvents, Such as kerosene, 8850- carried out in the wet grinding of the ore or in l ne. acetone. benzol, etc- In luti n they may an agitator or conditioning apparatus or in the be handled satisfactorily as ation rea nts- 30 flotation machine itself, B. Soluble lead salts such as lead acetate or The third step is to run t m, t any convenlead nitrate are used in aqueous solutions in quantional type flotation machine, the exact andi. titles from 0.5 lb. t0 8 lbs. per ton Of ore.

on of dilution being of no great importance There are several additional steps that we may mom one ore to four parts water up to one include in 0111 process to render Ores 11101'6 part ore to twelve parts water have been used amenable treatment These are herewith for dilution in obtaining satisfactory experimengiven' it be understwd that they are tal results. A frothing agent is now usually adde mt @ssentlaL t are:

ed, for example pine oil or any other convem 1. Preliminary roasting of the ore with free tional frother, if the soap is not suflicient to proaccess of air to rid the ore of carbon content. 40

duce the froth required. The quantity is left t 2- Contacting the are with dilute sulfuric acid the discretion f the operator. Also b f the (0.25% to 1.0% concentration) after pulping, to actual flotation is done, there is added for each convert the and Pb present to Insoluble sulfates and to neutralize excessive alkalinity of ton of ore being treated, one half pound or more the ore and then removing excess acid. 45

of a soluble lead salt, preferably lead acetate, the function of which is probably that of a selective gi f ;f g :f;g promoter as it permits the minerals containing to neutralize it thus rendering ulmecessary the uranium, such as camotite to float selectively Subsequent use of larger quantities f more the game mineralspensive reagents such as soaps. 50

The pulp in the machine is floated according to The amount of neutralization or softening to Wh v technique the machine demands, 11- be done bears a rough relation to the U308 con- I y m hanical or air agitation. The uranium tent of the ore. Low grade ores usually require material is carried up to the top in a froth or more neutralization than high grade ores for the scum and is either overflowed or removed by reason that they contain more gangue. It is the gangue materials (except 810:) that give the ore either its alkaline or acid character. The adaptation of the amount of neutralization or softening of the water or the pulp to the U:O| content of the ore lies distinctly within our invention. In any case where an ore is encountered that gives a pulp outside the range of pH slightly under 7 to 8 inclusive, neutralization or softening is usually practiced. In other words, the flotation process will proceed with the best results, when the pulp is neutral or slightly alkaline and it lies within the scope of the invention to make it so.

We claim as our invention:

1. The process of floating uranium ores which comprises pulping a uranium ore, adjusting the pH of the pulp to nearly 7 to 8, contacting the pulp with a dilute alkali soap solution and then subjecting said pulp to flotation procedure in the presence of a water-soluble lead salt.

2. A process according to claim 1 in which the pulp of a uranium ore is subjected to flotation in the presence of a frothing agent in addition to the soap.

3. A process according to claim 1 in which the pulp of a uranium ore is subjected to flotation in the presence of a silica depressant.

4. A process according to claim 1 in which the uranium ore is carnotite.

5. A process according to claim 1 in which the pulp is acidified with H2504 before adjustment of the pH to nearly 7 to 8.

6. The process of floating uranium ore which comprises pulping the ore with water, adjusting the pH of the pulp to the neighborhood of 7 to 8, contacting the pulp with an alkali metal soap solution of 0.25% to 1% strength, subjecting the so-prepared pulp to flotation procedure in the presence of a water soluble lead salt and removing the U30; containing froth thereby produced.

7. A process according to claim 6 in which pine oil is added to the pulp prior to flotation.

8. A process according to claim 6 in which sodium silicate is added to the pulp before subjecting the latter to flotation procedure.

9. A process according to claim 6 in which the uranium ore is carnotite.

a 10. A process according to claim 8 in which the water soluble lead salt is lead acetate.

11. The process of recovering a UaO: concentrate by flotation which comprises pulping a uranium ore with water, rendering the Ba, Ba and Pb salts in the pulp water insoluble, adjusting the pH of the pulp to the neighborhood of 7 to 8, contacting the pulp with a dilute alkali metal soap solution of not more than 1% strength, subjecting the so-prepared pulp to flotation procedure in the presence of a soluble lead salt in the proportion of 0.5 lb. to 8 lbs. per ton of ore and mechanically removing the U30: containing froth so produced.

12. A process according to claim 11 in which the uranium ore is carnotite.

13. A process according to claim 11 in which the flotation is conducted in the presence of sodium silicate.

14. A process according to claim 11 in which the lead salt is lead acetate.

15. A process according to claim 11 in which the soluble lead salt is lead nitrate.

16. A process according to claim 11 in which the Ra, Ba and Pb salts are rendered insoluble by being converted to their sulfates by preliminarily contacting the finely ground ore with dilute sulfuric acid.

17. The process of preparing a U30; concentrate containing from 8% to 30% UaOa by weight which comprises pulping a uranium ore containing from 0.5% to 3% UaOa selected from the group comprising carnotite, torbernite, autunite and the uraninites, adjusting the pH of the pulp to the neighborhood of neutrality to slightly alkaline, contacting the so-prepared pulp with an alkali metal soap solution of from 0.25% to 1.0% strength, adding a water soluble lead salt in the proportion of from 0.5 lb. to 8 lbs. per ton of ore, subjecting the mixture to agitation to produce a U30: containing froth and then separating the said froth from the pulp and the gangue.

HARRY HOWARD ARMSTRONG. ARTHUR BURLEY MENEFEE. 

